To start off, I'll think of a few things: Some Days Are Better Than Others sounds like a black background with a bunch of tiny neon colours zipping around. Elvis Presley And America, my favourite U2 song, is a myriad of deep aquatic colours of green and blue with blotches of black. Love And Peace Or Else reminds me of brown corderoy. Mercy is a bright, glowing, carnelian orange, like when you close your eyes and turn towards the sun.
If there was just a big old post about this, sorry- I've been on a vacation of sorts and very busy, so I haven't been reading my friendslist.